package Q617;

/**
 * 合并二叉树
 * @author 23737
 * @time 2021.12.1
 */
public class Test {
    public static void main(String[] args) {

    }
}

  class TreeNode {
     int val;
     TreeNode left;
     TreeNode right;
     TreeNode() {}
     TreeNode(int val) { this.val = val; }
     TreeNode(int val, TreeNode left, TreeNode right) {
         this.val = val;
         this.left = left;
         this.right = right;
     }
 }

/**
 * 递归
 */
class Solution {
    public TreeNode mergeTrees(TreeNode root1, TreeNode root2) {
        if(root1 == null){
            return root2;
        }
        if(root2 == null){
            return root1;
        }
        TreeNode treeNode = new TreeNode(root1.val+ root2.val);
        treeNode.left = mergeTrees(root1.left,root2.left);
        treeNode.right = mergeTrees(root1.right,root2.right);
        return treeNode;
    }
}
